Digital intercommunication systems typically work in half-duplex mode and do not include a central control station when all subscribers are fully connected. When carrying out a multi-party conversation in half-duplex mode, at one time, no more than one transmitting subscriber has a right to speak and occupies the physical channel to transmit voice signals.
In order to ensure that every subscriber has a chance to obtain the right to speak, a configuration is needed for handing over the right to speak among the multiple subscribers. Conventional intercommunication systems typically include some established polling rules for handing over the right to speak, or leave to each subscriber to fight freely for the right to speak. Such arrangements can be inefficient or may bring collision. When polling rules are used, a subscriber who wants to speak may have to wait for a long period of time before it is polled and given the right to speak. As a result, the communication efficiency may suffer. When subscribers are allowed to fight freely for the right to speak, collisions in the physical channel would likely occur if multiple subscribers want to speak at the same time. The back-off associated with such collisions can cause significant delay, and thus wasting precious physical channel resources. Accordingly, there is a need for improving the efficiency of handing over the right to speak among multiple subscribers in a multi-party conversation in intercommunication systems.